Paul_KD7HB:
Unless all the devices have had the same exposure history and age, you may get what you see. Google for "AM2302" and read the instructions on the last page on how to recover the humidity sensor to it's calibrated value.They also tell why the humidity sensor may become contaminated.
Paul
Two of the sensors have been used for some months now, and three of them were brand new, straight out of the box in which they came. Actually, the most consistent values are not from the newer sensors. When I bought them, they came in a long plastic strip with a slot with the size of each sensor. I guess it it is not impossible that they have been contaminated, but I doubt it's because the original packaging in which they were stored.
I tried to find a way to re-calibrate them, but I couldn't. I've read about the saturated salt solutions, but then I don't know how to correct the values that the sensor gives.
michinyon:
Your first data there kind of looks like nonsense.Are you missing commas or decimal points or something ?
I'm in Europe, so I usually use commas for decimal points. I don't know why one table uses the commas and other the points, I guess I copied the first one from an excel table, and the second one straight from Arduino's serial console.